diff --git a/include/stdex/base64 b/include/stdex/base64 new file mode 100644 index 000000000..e3ab42f09 --- /dev/null +++ b/include/stdex/base64 @@ -0,0 +1,279 @@ +/* + SPDX-License-Identifier: GPL-3.0-or-later + Copyright © 2016-2022 Amebis +*/ + +#pragma once + +#include +#include + + +namespace stdex +{ + /// + /// Base64 encoding session + /// + class base64_enc + { + public: + /// + /// Constructs blank encoding session + /// + inline base64_enc() noexcept : num(0) + { + buf[0] = 0; + buf[1] = 0; + buf[2] = 0; + } + + + /// + /// Encodes one block of information, and _appends_ it to the output + /// + /// \param[out] out Output + /// \param[in ] data Data to encode + /// \param[in ] size Length of `data` in bytes + /// \param[in ] is_last Is this the last block of data? + /// + template + inline void encode(_Inout_ std::basic_string<_Elem, _Traits, _Ax> &out, _In_bytecount_(size) const void *data, _In_ size_t size, _In_opt_ bool is_last = true) + { + assert(data || !size); + + // Preallocate output + out.reserve(out.size() + enc_size(size)); + + // Convert data character by character. + for (size_t i = 0;; i++) { + if (num >= 3) { + encode(out); + num = 0; + } + + if (i >= size) + break; + + buf[num++] = reinterpret_cast(data)[i]; + } + + // If this is the last block, flush the buffer. + if (is_last && num) { + encode(out, num); + num = 0; + } + } + + + /// + /// Resets encoding session + /// + inline void clear() noexcept + { + num = 0; + } + + + /// + /// Returns maximum encoded size + /// + /// \param size Number of bytes to encode + /// + /// \returns Maximum number of bytes for the encoded data of `size` length + /// + inline size_t enc_size(size_t size) const noexcept + { + return ((num + size + 2)/3)*4; + } + + + protected: + /// + /// Encodes one complete internal buffer of data + /// + template + inline void encode(_Inout_ std::basic_string<_Elem, _Traits, _Ax> &out) + { + out += base64_enc_lookup[ buf[0] >> 2 ]; + out += base64_enc_lookup[((buf[0] << 4) | (buf[1] >> 4)) & 0x3f]; + out += base64_enc_lookup[((buf[1] << 2) | (buf[2] >> 6)) & 0x3f]; + out += base64_enc_lookup[ buf[2] & 0x3f]; + } + + + /// + /// Encodes partial internal buffer of data + /// + template + inline void encode(_Inout_ std::basic_string<_Elem, _Traits, _Ax> &out, _In_ size_t size) + { + if (size > 0) { + out += base64_enc_lookup[buf[0] >> 2]; + if (size > 1) { + out += base64_enc_lookup[((buf[0] << 4) | (buf[1] >> 4)) & 0x3f]; + if (size > 2) { + out += base64_enc_lookup[((buf[1] << 2) | (buf[2] >> 6)) & 0x3f]; + out += base64_enc_lookup[buf[2] & 0x3f]; + } else { + out += base64_enc_lookup[(buf[1] << 2) & 0x3f]; + out += '='; + } + } else { + out += base64_enc_lookup[(buf[0] << 4) & 0x3f]; + out += '='; + out += '='; + } + } else { + out += '='; + out += '='; + out += '='; + out += '='; + } + } + + + protected: + unsigned char buf[3]; ///< Internal buffer + size_t num; ///< Number of bytes used in `buf` + }; + + + /// \cond internal + static const char base64_enc_lookup[64] = { + 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P', + 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z', 'a', 'b', 'c', 'd', 'e', 'f', + 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', + 'w', 'x', 'y', 'z', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '+', '/' + }; + /// \endcond + + + /// + /// Base64 decoding session + /// + class base64_dec + { + public: + /// + /// Constructs blank decoding session + /// + inline base64_dec() noexcept : num(0) + { + buf[0] = 0; + buf[1] = 0; + buf[2] = 0; + buf[3] = 0; + } + + + /// + /// Decodes one block of information, and _appends_ it to the output + /// + /// \param[out] out Output + /// \param[in ] is_last Was this the last block of data? + /// \param[in ] data Data to decode + /// \param[in ] size Length of `data` in bytes + /// + template + inline void decode(_Inout_ std::vector<_Ty, _Ax> &out, _Out_ bool &is_last, _In_z_count_(size) const _Tchr *data, _In_ size_t size) + { + is_last = false; + + // Trim data size to first terminator. + for (size_t k = 0; k < size; k++) + if (!data[k]) { size = k; break; } + + // Preallocate output + out.reserve(out.size() + dec_size(size)); + + for (size_t i = 0;; i++) { + if (num >= 4) { + // Buffer full; decode it. + size_t nibbles = decode(out); + num = 0; + if (nibbles < 3) { + is_last = true; + break; + } + } + + if (i >= size) + break; + + int x = data[i]; + if ((buf[num] = x < _countof(base64_dec_lookup) ? base64_dec_lookup[x] : 255) != 255) + num++; + } + } + + + /// + /// Resets decoding session + /// + inline void clear() noexcept + { + num = 0; + } + + + /// + /// Returns maximum decoded size + /// + /// \param size Number of bytes to decode + /// + /// \returns Maximum number of bytes for the decoded data of `size` length + /// + inline size_t dec_size(size_t size) const noexcept + { + return ((num + size + 3)/4)*3; + } + + + protected: + /// + /// Decodes one complete internal buffer of data + /// + template + inline size_t decode(_Inout_ std::vector<_Ty, _Ax> &out) + { + out.push_back((_Ty)(((buf[0] << 2) | (buf[1] >> 4)) & 0xff)); + if (buf[2] < 64) { + out.push_back((_Ty)(((buf[1] << 4) | (buf[2] >> 2)) & 0xff)); + if (buf[3] < 64) { + out.push_back((_Ty)(((buf[2] << 6) | buf[3]) & 0xff)); + return 3; + } else + return 2; + } else + return 1; + } + + + protected: + unsigned char buf[4]; ///< Internal buffer + size_t num; ///< Number of bytes used in `buf` + }; + + + /// \cond internal + static const unsigned char base64_dec_lookup[256] = { + /* 0 1 2 3 4 5 6 7 8 9 A B C D E F */ + /* 0 */ 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, + /* 1 */ 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, + /* 2 */ 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 62, 255, 255, 255, 63, + /* 3 */ 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 255, 255, 255, 64, 255, 255, + /* 4 */ 255, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, + /* 5 */ 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 255, 255, 255, 255, 255, + /* 6 */ 255, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, + /* 7 */ 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 255, 255, 255, 255, 255, + /* 8 */ 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, + /* 9 */ 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, + /* A */ 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, + /* B */ 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, + /* C */ 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, + /* D */ 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, + /* E */ 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, + /* F */ 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255 + }; + /// \endcond +}